The novel dihydronaphthyridine Ca2+ channel blocker CI-951 improves CBF, brain pHi, and EEG recovery in focal cerebral ischemia.
The effects of the novel dihydronaphthyridine Ca2+ antagonist CI-951 on focal cerebral ischemia were assessed during MCA occlusion in 30 white New Zealand rabbits under 1.0% halothane anesthesia. In vivo brain pHi and focal CBF were measured with umbelliferone fluorescence. Baseline normocapnic brain pHi and CBF were 7.02 +/- 0.02 and 48.4 +/- 2.9 ml/100 g/min, respectively. In the severe ischemic regions, 15 min postocclusion brain pHi and CBF were 6.62 +/- 0.04 and 14.4 +/- 0.7 ml/100 g/min in controls vs. 6.60 +/- 0.02 and 12.9 +/- 2.3 ml/100 g/min, respectively, in animals destined to receive CI-951. Twenty minutes after MCA occlusion, CI-951 was administered at 0.5 microgram/kg/min and brain pHi and CBF were determined in both regions of severe and moderate ischemia for 4 h postocclusion. Control severe ischemic sites demonstrated no significant improvement in brain pHi and only mild increases in CBF over the next 4 h. CI-951 caused significant improvement in both of these parameters. Postocclusion 4 h brain pHi and CBF measured 6.69 +/- 0.04 and 18.5 +/- 3.2 ml/100 g/min in controls vs. 7.01 +/- 0.04 and 41.7 +/- 5.3 ml/100 g/min, respectively, in CI-951 animals (p less than 0.001). Similar improvements were observed in moderate ischemic sites. In animals that demonstrated postocclusion EEG attenuation, 75% of CI-951 animals had EEG recovery as compared to 18% in controls. CI-951 may be a useful therapeutic agent for focal cerebral ischemia if histological and outcome studies verify these data.
Meyer
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FB
Neurosurgical Cerebrovascular Research Center, Mayo Clinic, Rochester, MN 55903.
Anderson
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RE
Sundt
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TM
D000818:Animals; D001921:Brain / Q000378:metabolism* / Q000503:physiopathology; D002545:Brain Ischemia / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D055598:Chemical Phenomena; D002621:Chemistry; D003643:Death; D004569:Electroencephalography; D006859:Hydrogen / Q000378:metabolism* / Q000502:physiology; D009287:Naphthyridines / Q000494:pharmacology*; D011817:Rabbits
D009287:Naphthyridines; C062630:CI 951; D006859:Hydrogen